El Castillo Cave is an archaeological site located in Puente Viesgo, Cantabria, Spain that contains the oldest known cave art in the world dating back 120,000 years. The cave walls contain paintings of hands, bison, deer, horses and other enigmatic symbols left by both Neanderthals and early modern humans. Archaeologists have discovered remains from the Lower Paleolithic through Bronze Age periods that provide clues about the lifestyles and mentality of the paleolithic humans who inhabited the cave.